Conventionally, there is proposed an active vibration noise control device for controlling an engine sound heard in a vehicle interior by a controlled sound output from a speaker so as to decrease the engine sound at a position of passenger's ear. For example, noticing that a vibration noise in a vehicle interior is generated in synchronization with a revolution of an output axis of an engine, there is proposed a technique for canceling the noise in the vehicle interior on the basis of the revolution of the output axis of the engine by using an adaptive notch filter so that the vehicle interior becomes silent.
In addition, there is proposed a technique for decreasing the vibration noise at a position (for example, ear position) other than an installation position of the microphone (see Patent References 1 and 2, for example). Concretely, in Patent Reference-2, there is proposed a technique for correcting an output signal from one speaker by using a filter coefficient in order to prevent an interference of control sounds from plural speakers, which sometimes occurs by the technique described in Patent Reference-1.